path: root/camel/providers/imap/camel-imap-store.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-imap-store.c : class for an imap store */

/*
 *  Authors: Jeffrey Stedfast <fejj@helixcode.com>
 *
 *  Copyright 2000 Helix Code, Inc. (www.helixcode.com)
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Street #330, Boston, MA 02111-1307, USA.
 *
 */


#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <e-util/e-util.h>

#include "camel-imap-store.h"
#include "camel-imap-folder.h"
#include "camel-imap-utils.h"
#include "camel-folder.h"
#include "camel-exception.h"
#include "camel-session.h"
#include "camel-stream.h"
#include "camel-stream-buffer.h"
#include "camel-stream-fs.h"
#include "camel-url.h"
#include "string-utils.h"

#define d(x) x

/* Specified in RFC 2060 */
#define IMAP_PORT 143

static CamelRemoteStoreClass *remote_store_class = NULL;

static gboolean imap_create (CamelFolder *folder, CamelException *ex);
static void imap_post_connect (CamelRemoteStore *remote_store, CamelException *ex);
static void imap_pre_disconnect (CamelRemoteStore *remote_store, CamelException *ex);
static GList *query_auth_types_generic (CamelService *service, CamelException *ex);
static GList *query_auth_types_connected (CamelService *service, CamelException *ex);
static CamelFolder *get_folder (CamelStore *store, const char *folder_name, gboolean create,
                CamelException *ex);
static void imap_keepalive (CamelRemoteStore *store);
/*static gboolean stream_is_alive (CamelStream *istream);*/
static int camel_imap_status (char *cmdid, char *respbuf);

static void
camel_imap_store_class_init (CamelImapStoreClass *camel_imap_store_class)
{
    /* virtual method overload */
    CamelServiceClass *camel_service_class =
        CAMEL_SERVICE_CLASS (camel_imap_store_class);
    CamelStoreClass *camel_store_class =
        CAMEL_STORE_CLASS (camel_imap_store_class);
    CamelRemoteStoreClass *camel_remote_store_class =
        CAMEL_REMOTE_STORE_CLASS (camel_imap_store_class);
    
    remote_store_class = CAMEL_REMOTE_STORE_CLASS(camel_type_get_global_classfuncs 
                              (camel_remote_store_get_type ()));

    /* virtual method overload */
    camel_service_class->query_auth_types_generic = query_auth_types_generic;
    camel_service_class->query_auth_types_connected = query_auth_types_connected;

    camel_store_class->get_folder = get_folder;

    camel_remote_store_class->post_connect = imap_post_connect;
    camel_remote_store_class->pre_disconnect = imap_pre_disconnect;
    camel_remote_store_class->keepalive = imap_keepalive;
}

static void
camel_imap_store_init (gpointer object, gpointer klass)
{
    CamelService *service = CAMEL_SERVICE (object);
    CamelImapStore *imap_store = CAMEL_IMAP_STORE (object);

    service->url_flags |= (CAMEL_SERVICE_URL_NEED_USER |
                   CAMEL_SERVICE_URL_NEED_HOST |
                   CAMEL_SERVICE_URL_ALLOW_PATH);

    imap_store->dir_sep = g_strdup ("/"); /*default*/
    imap_store->current_folder = NULL;
}

CamelType
camel_imap_store_get_type (void)
{
    static CamelType camel_imap_store_type = CAMEL_INVALID_TYPE;
    
    if (camel_imap_store_type == CAMEL_INVALID_TYPE)    {
        camel_imap_store_type = camel_type_register (CAMEL_REMOTE_STORE_TYPE, "CamelImapStore",
                                 sizeof (CamelImapStore),
                                 sizeof (CamelImapStoreClass),
                                 (CamelObjectClassInitFunc) camel_imap_store_class_init,
                                 NULL,
                                 (CamelObjectInitFunc) camel_imap_store_init,
                                 (CamelObjectFinalizeFunc) NULL);
    }
    
    return camel_imap_store_type;
}

static CamelServiceAuthType password_authtype = {
    "Password",
    
    "This option will connect to the IMAP server using a "
    "plaintext password.",
    
    "",
    TRUE
};

static GList *
query_auth_types_connected (CamelService *service, CamelException *ex)
{
#if 0   
    GList *ret = NULL;
    gboolean passwd = TRUE;
    
    if (service->url) {
        passwd = try_connect (service, ex);
        if (camel_exception_get_id (ex) != CAMEL_EXCEPTION_NONE)
            return NULL;
    }
    
    if (passwd)
        ret = g_list_append (ret, &password_authtype);
    
    if (!ret) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                      "Could not connect to IMAP server on %s.",
                      service->url->host ? service->url->host : 
                      "(unknown host)");
    }                     
    
    return ret;
#else
    g_warning ("imap::query_auth_types_connected: not implemented. Defaulting.");
    /* FIXME: use the classfunc instead of the local? */
    return query_auth_types_generic (service, ex);
#endif
}

static GList *
query_auth_types_generic (CamelService *service, CamelException *ex)
{
    GList *prev;
    
    prev = CAMEL_SERVICE_CLASS (remote_store_class)->query_auth_types_generic (service, ex);
    return g_list_prepend (prev, &password_authtype);
}

static void
imap_post_connect (CamelRemoteStore *remote_store, CamelException *ex)
{
    CamelService *service = CAMEL_SERVICE (remote_store);
    CamelImapStore *store = CAMEL_IMAP_STORE (remote_store);
    CamelSession *session = camel_service_get_session (CAMEL_SERVICE (store));
    gint status;
    gchar *buf, *result, *errbuf = NULL;
    gboolean authenticated = FALSE;
    
    store->command = 0;
    g_free (store->dir_sep);
    store->dir_sep = g_strdup ("/");  /* default dir sep */
    
    /* Read the greeting, if any. */
    if (camel_remote_store_recv_line (remote_store, &buf, ex) < 0) {
        return;
    }
    g_free (buf);
    
    /* authenticate the user */
    while (!authenticated) {
        if (errbuf) {
            /* We need to un-cache the password before prompting again */
            camel_session_query_authenticator (session,
                               CAMEL_AUTHENTICATOR_TELL, NULL,
                               TRUE, service, "password", ex);
            g_free (service->url->passwd);
            service->url->passwd = NULL;
        }
        
        if (!service->url->authmech && !service->url->passwd) {
            gchar *prompt;
            
            prompt = g_strdup_printf ("%sPlease enter the IMAP password for %s@%s",
                          errbuf ? errbuf : "", service->url->user, service->url->host);
            service->url->passwd =
                camel_session_query_authenticator (session,
                                   CAMEL_AUTHENTICATOR_ASK, prompt,
                                   TRUE, service, "password", ex);
            g_free (prompt);
            g_free (errbuf);
            errbuf = NULL;
            
            if (!service->url->passwd) {
                camel_service_disconnect (service, ex);
                return;
            }
        }
        
        status = camel_imap_command (store, NULL, ex, "LOGIN \"%s\" \"%s\"",
                         service->url->user,
                         service->url->passwd);
        
        if (status != CAMEL_IMAP_OK) {
            errbuf = g_strdup_printf ("Unable to authenticate to IMAP server.\n"
                          "%s\n\n",
                          camel_exception_get_description (ex));
        } else {
            g_message ("IMAP Service sucessfully authenticated user %s", service->url->user);
            authenticated = TRUE;
        }
    }
    
    /* Now lets find out the IMAP capabilities */
    status = camel_imap_command_extended (store, NULL, &result, ex, "CAPABILITY");
    
    if (status != CAMEL_IMAP_OK) {
        /* Non-fatal error... (ex is set) */
    }
    
    /* parse for capabilities here. */
    if (e_strstrcase (result, "IMAP4REV1"))
        store->server_level = IMAP_LEVEL_IMAP4REV1;
    else if (e_strstrcase (result, "IMAP4"))
        store->server_level = IMAP_LEVEL_IMAP4;
    else
        store->server_level = IMAP_LEVEL_UNKNOWN;
    
    if ((store->server_level >= IMAP_LEVEL_IMAP4REV1) || (e_strstrcase (result, "STATUS")))
        store->has_status_capability = TRUE;
    else
        store->has_status_capability = FALSE;
    
    g_free (result);
    
    /* We now need to find out which directory separator this daemon uses */
    status = camel_imap_command_extended (store, NULL, &result, ex, "LIST \"\" \"\"");
    
    if (status != CAMEL_IMAP_OK) {
        /* Again, this is non-fatal */
    } else {
        char *flags, *sep, *folder;
        
        if (imap_parse_list_response (result, "", &flags, &sep, &folder)) {
            if (*sep) {
                g_free (store->dir_sep);
                store->dir_sep = g_strdup (sep);
            }
        }
        
        g_free (flags);
        g_free (sep);
        g_free (folder);
    }
    
    g_free (result);
    
    CAMEL_REMOTE_STORE_CLASS (remote_store_class)->post_connect (remote_store, ex);
}

static void
imap_pre_disconnect (CamelRemoteStore *remote_store, CamelException *ex)
{
    CamelImapStore *store = CAMEL_IMAP_STORE (remote_store);
    char *result;
    int status;
    
    /* send the logout command */
    status = camel_imap_command_extended (store, NULL, &result, ex, "LOGOUT");
    if (status != CAMEL_IMAP_OK) {
        /* Oh fuck it, we're disconnecting anyway... */
    }
    g_free (result);
    
    g_free (store->dir_sep);
    store->dir_sep = NULL;
    
    store->current_folder = NULL;
    
    CAMEL_REMOTE_STORE_CLASS (remote_store_class)->pre_disconnect (remote_store, ex);
}

const gchar *
camel_imap_store_get_toplevel_dir (CamelImapStore *store)
{
    CamelURL *url = CAMEL_SERVICE (store)->url;
    
    g_assert (url != NULL);
    return url->path;
}

static gboolean
imap_folder_exists (CamelFolder *folder, CamelException *ex)
{
    CamelStore *store = CAMEL_STORE (folder->parent_store);
    CamelURL *url = CAMEL_SERVICE (store)->url;
    gchar *result, *folder_path, *dir_sep;
    gint status;
    
    dir_sep = CAMEL_IMAP_STORE (folder->parent_store)->dir_sep;
    
    g_return_val_if_fail (dir_sep, FALSE);
    
    if (url && url->path && *(url->path + 1) && strcmp (folder->full_name, "INBOX"))
        folder_path = g_strdup_printf ("%s%s%s", url->path + 1, dir_sep, folder->full_name);
    else
        folder_path = g_strdup (folder->full_name);
    
    status = camel_imap_command_extended (CAMEL_IMAP_STORE (folder->parent_store), NULL,
                          &result, ex, "EXAMINE %s", folder_path);
    
    if (status != CAMEL_IMAP_OK) {
        g_free (result);
        g_free (folder_path);
        return FALSE;
    }
    g_free (folder_path);
    g_free (result);
    
    return TRUE;
}

static gboolean
imap_create (CamelFolder *folder, CamelException *ex)
{
    CamelStore *store = CAMEL_STORE (folder->parent_store);
    CamelURL *url = CAMEL_SERVICE (store)->url;
    gchar *result, *folder_path, *dir_sep;
    gint status;
    
    g_return_val_if_fail (folder != NULL, FALSE);
    
    if (!(folder->full_name || folder->name)) {
        camel_exception_set (ex, CAMEL_EXCEPTION_FOLDER_INVALID,
                     "invalid folder path. Use set_name ?");
        return FALSE;
    }
    
    if (!strcmp (folder->full_name, "INBOX"))
        return TRUE;
    
    if (imap_folder_exists (folder, ex))
        return TRUE;
    
        /* create the directory for the subfolder */
    dir_sep = CAMEL_IMAP_STORE (folder->parent_store)->dir_sep;
    
    g_return_val_if_fail (dir_sep, FALSE);
    
    if (url && url->path && *(url->path + 1) && strcmp (folder->full_name, "INBOX"))
        folder_path = g_strdup_printf ("%s%s%s", url->path + 1, dir_sep, folder->full_name);
    else
        folder_path = g_strdup (folder->full_name);
    
    status = camel_imap_command_extended (CAMEL_IMAP_STORE (folder->parent_store), NULL,
                          &result, ex, "CREATE %s", folder_path);
    g_free (folder_path);
    
    if (status != CAMEL_IMAP_OK)
        return FALSE;
    
    return TRUE;
}

static gboolean
folder_is_selectable (CamelStore *store, const char *folder_path, CamelException *ex)
{
    char *result, *flags, *sep, *folder;
    int status;
    
    if (!strcmp (folder_path, "INBOX"))
        return TRUE;
    
    status = camel_imap_command_extended (CAMEL_IMAP_STORE (store), NULL,
                          &result, ex, "LIST \"\" %s", folder_path);
    if (status != CAMEL_IMAP_OK)
        return FALSE;
    
    if (imap_parse_list_response (result, "", &flags, &sep, &folder)) {
        gboolean retval;
        
        retval = !e_strstrcase (flags, "NoSelect");
        g_free (flags);
        g_free (sep);
        g_free (folder);
        
        return retval;
    }
    g_free (flags);
    g_free (sep);
    g_free (folder);
    
    return FALSE;
}

static CamelFolder *
get_folder (CamelStore *store, const char *folder_name, gboolean create, CamelException *ex)
{
    CamelURL *url = CAMEL_SERVICE (store)->url;
    CamelFolder *new_folder;
    char *folder_path, *dir_sep;
    
    g_return_val_if_fail (store != NULL, NULL);
    g_return_val_if_fail (folder_name != NULL, NULL);
    
    dir_sep = CAMEL_IMAP_STORE (store)->dir_sep;
    
    /* if we're trying to get the top-level dir, we really want the namespace */
    if (!dir_sep || !strcmp (folder_name, dir_sep))
        folder_path = g_strdup (url->path + 1);
    else
        folder_path = g_strdup (folder_name);
    
    new_folder = camel_imap_folder_new (store, folder_path, ex);
    
    /* this is the top-level dir, we already know it exists - it has to! */
    if (!strcmp (folder_name, dir_sep))
        return new_folder;
    
    if (create && !imap_create (new_folder, ex)) {
        if (!folder_is_selectable (store, folder_path, ex)) {
            camel_exception_clear (ex);
            new_folder->can_hold_messages = FALSE;
            return new_folder;
        } else {
            g_free (folder_path);
            camel_object_unref (CAMEL_OBJECT (new_folder));     
            return NULL;
        }
    }
    
    return new_folder;
}

static void
imap_keepalive (CamelRemoteStore *store)
{
    CamelImapStore *imap_store = CAMEL_IMAP_STORE (store);
    char *result;
    int status;
    CamelException ex;
    
    camel_exception_init (&ex);
    status = camel_imap_command_extended (imap_store, imap_store->current_folder, 
                          &result, &ex, "NOOP");
    camel_exception_clear (&ex);
    g_free (result);
}

#if 0
static gboolean
stream_is_alive (CamelStream *istream)
{
    CamelStreamFs *fs_stream;
    char buf;
    
    g_return_val_if_fail (istream != NULL, FALSE);
    
    fs_stream = CAMEL_STREAM_FS (CAMEL_STREAM_BUFFER (istream)->stream);
    g_return_val_if_fail (fs_stream->fd != -1, FALSE);
    
    if (read (fs_stream->fd, (void *) &buf, 0) == 0)
        return TRUE;
    
    return FALSE;
}
#endif

static int
camel_imap_status (char *cmdid, char *respbuf)
{
    char *retcode;
    
    if (respbuf) {
        if (!strncmp (respbuf, cmdid, strlen (cmdid))) {
            retcode = imap_next_word (respbuf);
            
            if (!strncmp (retcode, "OK", 2))
                return CAMEL_IMAP_OK;
            else if (!strncmp (retcode, "NO", 2))
                return CAMEL_IMAP_NO;
            else if (!strncmp (retcode, "BAD", 3))
                return CAMEL_IMAP_BAD;
        }
    }
    
    return CAMEL_IMAP_FAIL;
}

static gint
check_current_folder (CamelImapStore *store, CamelFolder *folder, char *fmt, CamelException *ex)
{
    CamelURL *url = CAMEL_SERVICE (store)->url;
    char *r, *folder_path, *dir_sep;
    int s;
    
    if (!folder)
        return CAMEL_IMAP_OK;
    if (store->current_folder == folder)
        return CAMEL_IMAP_OK;
    if (strncmp (fmt, "CREATE", 5) == 0)
        return CAMEL_IMAP_OK;
    
    dir_sep = store->dir_sep;
    
    if (url && url->path && *(url->path + 1) && strcmp (folder->full_name, "INBOX"))
        folder_path = g_strdup_printf ("%s%s%s", url->path + 1, dir_sep, folder->full_name);
    else
        folder_path = g_strdup (folder->full_name);
        
    s = camel_imap_command_extended (store, NULL, &r, ex, "SELECT %s", folder_path);
    g_free (folder_path);
    
    if (!r || s != CAMEL_IMAP_OK) {
        store->current_folder = NULL;
        return s;
    }
    
    g_free (r);
    store->current_folder = folder;
    return CAMEL_IMAP_OK;
}

static gint
send_command (CamelImapStore *store, char **cmdid, char *fmt, va_list ap, CamelException *ex)
{
    gchar *cmdbuf;
    
    *cmdid = g_strdup_printf ("A%.5d", store->command++);
    
    cmdbuf = g_strdup_vprintf (fmt, ap);
    
    if (camel_remote_store_send_string (CAMEL_REMOTE_STORE (store), ex, "%s %s\r\n", *cmdid, cmdbuf) < 0) {
        g_free (cmdbuf);
        g_free (*cmdid);
        *cmdid = NULL;
        return CAMEL_IMAP_FAIL;
    }
    
    g_free (cmdbuf);
    return CAMEL_IMAP_OK;
}

static gint
slurp_response (CamelImapStore *store, CamelFolder *folder, char *cmdid, char **ret,
        gboolean stop_on_plus, CamelException *ex)
{
    gint status = CAMEL_IMAP_OK;
    GPtrArray *data, *expunged;
    gchar *respbuf;
    guint32 len = 0;
    gint recent = 0;
    gint i;
    
    data = g_ptr_array_new ();
    expunged = g_ptr_array_new ();
    
    while (1) {
        if (camel_remote_store_recv_line (CAMEL_REMOTE_STORE (store), &respbuf, ex) < 0)
            return CAMEL_IMAP_FAIL;
        
        g_ptr_array_add (data, respbuf);
        len += strlen (respbuf) + 1;
        
        /* IMAP's last response starts with our command id or, sometimes, a plus */ 
        if (stop_on_plus && *respbuf == '+') {
            status = CAMEL_IMAP_PLUS;
            break;
        }
        
        if (!strncmp (respbuf, cmdid, strlen (cmdid))) {
            status = camel_imap_status (cmdid, respbuf);
            break;
        }
        
        /* If recent or expunge flags were somehow set and this
           response doesn't begin with a '*' then
           recent/expunged must have been misdetected */
        if ((recent || expunged->len > 0) && *respbuf != '*') {
            d(fprintf (stderr, "hmmm, someone tried to pull a fast one on us.\n"));
            
            recent = 0;
            
            for (i = 0; i < expunged->len; i++) {
                g_free (expunged->pdata[i]);
                g_ptr_array_remove_index (expunged, i);
            }
        }
        
        /* Check for a RECENT in the untagged response */
        if (*respbuf == '*') {
            if (strstr (respbuf, "RECENT")) {
                char *rcnt;
                
                d(fprintf (stderr, "*** We may have found a 'RECENT' flag: %s\n", respbuf));
                /* Make sure it's in the form: "* %d RECENT" */
                rcnt = imap_next_word (respbuf);
                if (*rcnt >= '0' && *rcnt <= '9' && !strncmp ("RECENT", imap_next_word (rcnt), 6))
                    recent = atoi (rcnt);
            } else if (strstr (respbuf, "EXPUNGE")) {
                char *id_str;
                int id;
                
                d(fprintf (stderr, "*** We may have found an 'EXPUNGE' flag: %s\n", respbuf));
                /* Make sure it's in the form: "* %d EXPUNGE" */
                id_str = imap_next_word (respbuf);
                if (*id_str >= '0' && *id_str <= '9' && !strncmp ("EXPUNGE", imap_next_word (id_str), 7)) {
                    id = atoi (id_str);
                    g_ptr_array_add (expunged, g_strdup_printf ("%d", id));
                }
            }
        }
    }
    
    /* Apply the 'recent' changes */
    if (folder && recent > 0)
        camel_imap_folder_changed (folder, recent, expunged, ex);
    
    if (status == CAMEL_IMAP_OK || status == CAMEL_IMAP_PLUS) {
        gchar *p;
        
        /* Command succeeded! Put the output into one big
         * string of love. */
        
        *ret = g_new (char, len + 1);
        p = *ret;
        
        for (i = 0; i < data->len; i++) {
            char *datap;
            
            datap = (char *) data->pdata[i];
            if (*datap == '.')
                datap++;
            len = strlen (datap);
            memcpy (p, datap, len);
            p += len;
            *p++ = '\n';
        }
        
        *p = '\0';
    } else {
        /* Bummer. Try to grab what the server said. */
        if (respbuf) {
            char *word;
            
            word = imap_next_word (respbuf); /* should now point to status */
            
            word = imap_next_word (word);    /* points to fail message, if there is one */
            
            camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                          "IMAP command failed: %s", word);
        }
        
        *ret = NULL;
    }
    
    /* Can this be put into the 'if succeeded' bit?
     * Or can a failed command generate untagged responses? */
    
    for (i = 0; i < data->len; i++)
        g_free (data->pdata[i]);
    g_ptr_array_free (data, TRUE);
    
    for (i = 0; i < expunged->len; i++)
        g_free (expunged->pdata[i]);
    g_ptr_array_free (expunged, TRUE);
    
    return status;
}

/* frees cmdid! */
static gint
parse_single_line (CamelImapStore *store, char *cmdid, CamelException *ex)
{
    char *respbuf;
    gint status;
    char *word;
    
    if (camel_remote_store_recv_line (CAMEL_REMOTE_STORE (store), &respbuf, ex) < 0)
        return CAMEL_IMAP_FAIL;
    
    /* Assume that buf indeed starts with cmdid; then
     * it can only start with a plus when the slurper
     * found a valid plus. So no need to check for
     * stop_on_plus.
     */
    
    if (*respbuf == '+') {
        g_free (cmdid);
        return CAMEL_IMAP_PLUS;
    }
    
    status = camel_imap_status (cmdid, respbuf);
    g_free (cmdid);
    
    if (status == CAMEL_IMAP_OK)
        return status;
    
    word = imap_next_word (respbuf); /* points to status */
    word = imap_next_word (word);    /* points to fail message, if there is one */
    
    camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                  "IMAP command failed: %s", word);
    return status;
}

/**
 * camel_imap_command: Send a command to a IMAP server.
 * @store: the IMAP store
 * @folder: The folder to perform the operation in
 * @ret: a pointer to return the full server response in
 * @ex: a CamelException.
 * @fmt: a printf-style format string, followed by arguments
 * 
 * This camel method sends the command specified by @fmt and the following
 * arguments to the connected IMAP store specified by @store. It then
 * reads the server's response and parses out the status code. If
 * the caller passed a non-NULL pointer for @ret, camel_imap_command
 * will set it to point to a buffer containing the rest of the
 * response from the IMAP server. (If @ret was passed but there was
 * no extended response, @ret will be set to NULL.) The caller function is
 * responsible for freeing @ret.
 * 
 * Return value: one of CAMEL_IMAP_OK (command executed successfully),
 * CAMEL_IMAP_NO (operational error message), CAMEL_IMAP_BAD (error
 * message from the server), or CAMEL_IMAP_FAIL (a protocol-level error
 * occurred, and Camel is uncertain of the result of the command.)
 **/
gint
camel_imap_command (CamelImapStore *store, CamelFolder *folder, CamelException *ex, char *fmt, ...)
{
    gchar *cmdid;
    va_list ap;
    gint status = CAMEL_IMAP_OK;
    
    /* check for current folder */
    status = check_current_folder (store, folder, fmt, ex);
    if (status != CAMEL_IMAP_OK)
        return status;
    
    /* send the command */
    va_start (ap, fmt);
    status = send_command (store, &cmdid, fmt, ap, ex);
    va_end (ap);
    if (status != CAMEL_IMAP_OK)
        return status;
    
    return parse_single_line (store, cmdid, ex);
}

/**
 * camel_imap_command_extended: Send a command to a IMAP server and get
 * a multi-line response.
 * @store: the IMAP store
 * @folder: The folder to perform the operation in
 * @ret: a pointer to return the full server response in
 * @fmt: a printf-style format string, followed by arguments
 *
 * This camel method sends the IMAP command specified by @fmt and the
 * following arguments to the IMAP store specified by @store. If the
 * store is in a disconnected state, camel_imap_command_extended will first
 * re-connect the store before sending the specified IMAP command. It then
 * reads the server's response and parses out the status code. If the caller
 * passed a non-NULL pointer for @ret, camel_imap_command_extended will set
 * it to point to a buffer containing the rest of the response from the IMAP
 * server. (If @ret was passed but there was no extended response, @ret will
 * be set to NULL.) The caller function is responsible for freeing @ret.
 * 
 * This camel method gets the additional data returned by "multi-line" IMAP
 * commands, such as SELECT, LIST, FETCH, and various other commands.
 * The returned data is un-byte-stuffed, and has lines termined by
 * newlines rather than CR/LF pairs.
 * 
 * Return value: one of CAMEL_IMAP_OK (command executed successfully),
 * CAMEL_IMAP_NO (operational error message), CAMEL_IMAP_BAD (error
 * message from the server), or CAMEL_IMAP_FAIL (a protocol-level error
 * occurred, and Camel is uncertain of the result of the command.)
 **/

gint
camel_imap_command_extended (CamelImapStore *store, CamelFolder *folder, char **ret, CamelException *ex, char *fmt, ...)
{
    gint status = CAMEL_IMAP_OK;
    gchar *cmdid;
    va_list ap;
    
    status = check_current_folder (store, folder, fmt, ex);
    if (status != CAMEL_IMAP_OK)
        return status;
    
    /* send the command */
    va_start (ap, fmt);
    status = send_command (store, &cmdid, fmt, ap, ex);
    va_end (ap);
    if (status != CAMEL_IMAP_OK)
        return status;
    
    return slurp_response (store, folder, cmdid, ret, FALSE, ex);
}

/**
 * camel_imap_command_preliminary: Send a preliminary command to the
 * IMAP server.
 * @store: the IMAP store
 * @cmdid: a pointer to return the command identifier (for use in
 * camel_imap_command_continuation)
 * @fmt: a printf-style format string, followed by arguments
 * 
 * This camel method sends a preliminary IMAP command specified by
 * @fmt and the following arguments to the IMAP store specified by
 * @store. This function is meant for use with multi-transactional
 * IMAP communications like Kerberos authentication and APPEND.
 * 
 * If the caller passed a non-NULL pointer for @ret,
 * camel_imap_command_preliminary will set it to point to a buffer
 * containing the rest of the response from the IMAP server. The
 * caller function is responsible for freeing @ret.
 * 
 * Return value: one of CAMEL_IMAP_PLUS, CAMEL_IMAP_OK,  or CAMEL_IMAP_FAIL
 * 
 * Note: on success (CAMEL_IMAP_PLUS), you will need to follow up with
 * a camel_imap_command_continuation call.
 **/
gint
camel_imap_command_preliminary (CamelImapStore *store, char **cmdid, CamelException *ex, char *fmt, ...)
{
    gint status = CAMEL_IMAP_OK;
    va_list ap;
    
    /* send the command */
    va_start (ap, fmt);
    status = send_command (store, cmdid, fmt, ap, ex);
    va_end (ap);
    if (status != CAMEL_IMAP_OK)
        return status;
    
    /* Read the response */
    return parse_single_line (store, g_strdup (*cmdid), ex);
}

/**
 * camel_imap_command_continuation: Handle another transaction with the IMAP
 * server and possibly get a multi-line response.
 * @store: the IMAP store
 * @cmdid: The command identifier returned from camel_imap_command_preliminary
 * @ret: a pointer to return the full server response in
 * @cmdbuf: buffer containing the response/request data
 *
 * This method is for sending continuing responses to the IMAP server. Meant
 * to be used as a followup to camel_imap_command_preliminary.
 * camel_imap_command_continuation will set @ret to point to a buffer
 * containing the rest of the response from the IMAP server. The
 * caller function is responsible for freeing @ret.
 * 
 * Return value: one of CAMEL_IMAP_PLUS (command requires additional data),
 * CAMEL_IMAP_OK (command executed successfully),
 * CAMEL_IMAP_NO (operational error message),
 * CAMEL_IMAP_BAD (error message from the server), or
 * CAMEL_IMAP_FAIL (a protocol-level error occurred, and Camel is uncertain
 * of the result of the command.)
 **/
gint
camel_imap_command_continuation (CamelImapStore *store, char **ret, char *cmdid, char *cmdbuf, CamelException *ex)
{
    if (camel_remote_store_send_string (CAMEL_REMOTE_STORE (store), ex, "%s\r\n", cmdbuf) < 0) {
        if (ret)
            *ret = NULL;
        return CAMEL_IMAP_FAIL;
    }
    
    return slurp_response (store, NULL, cmdid, ret, TRUE, ex);
}

/**
 * camel_imap_command_continuation_with_stream: Handle another transaction with the IMAP
 * server and possibly get a multi-line response.
 * @store: the IMAP store
 * @cmdid: The command identifier returned from camel_imap_command_preliminary
 * @ret: a pointer to return the full server response in
 * @cstream: a CamelStream containing a continuation response.
 * 
 * This method is for sending continuing responses to the IMAP server. Meant
 * to be used as a followup to camel_imap_command_preliminary.
 * camel_imap_command_continuation will set @ret to point to a buffer
 * containing the rest of the response from the IMAP server. The
 * caller function is responsible for freeing @ret.
 * 
 * Return value: one of CAMEL_IMAP_PLUS (command requires additional data),
 * CAMEL_IMAP_OK (command executed successfully),
 * CAMEL_IMAP_NO (operational error message),
 * CAMEL_IMAP_BAD (error message from the server), or
 * CAMEL_IMAP_FAIL (a protocol-level error occurred, and Camel is uncertain
 * of the result of the command.)
 **/
gint
camel_imap_command_continuation_with_stream (CamelImapStore *store, char **ret, char *cmdid,
                         CamelStream *cstream, CamelException *ex)
{
    if (camel_remote_store_send_stream (CAMEL_REMOTE_STORE (store), cstream, ex) < 0) {
        if (ret)
            *ret = NULL;
        return CAMEL_IMAP_FAIL;
    }
    
    return slurp_response (store, NULL, cmdid, ret, TRUE, ex);
}